SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 3 minutes ago, eaglescout526 said: I mean honestly the only person in the world I know who has the MS1700 is nickintime and I happen to have an ECU tester and so do 30 people on eBay. But the only absolutely last thing is the ECU and wiring harness. Should I be attempting to replace the TPS? I've replaced the MAP within a few months of getting the truck in 2018. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 5, 2020 Share Posted May 5, 2020 If the MAP went bad it would struggle to accelerate right and idle either high or low. I wouldn't replace the TPS until the proper voltage gets delivered to both sensors. Like I said, they aren't getting the 5V and the sensors need the 5V to "run" themselves to send data to the ECU. I don't think throwing new sensors will solve the issue. Just for giggles, how do the spark plugs look? Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 1 minute ago, eaglescout526 said: If the MAP went bad it would struggle to accelerate right and idle either high or low. I wouldn't replace the TPS until the proper voltage gets delivered to both sensors. Like I said, they aren't getting the 5V and the sensors need the 5V to "run" themselves to send data to the ECU. I don't think throwing new sensors will solve the issue. Just for giggles, how do the spark plugs look? I replaced the spark plugs two or three days ago. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 5, 2020 Share Posted May 5, 2020 Ok. Theres not a ballast resistor anywhere is there? And we have confirmed the pump runs for both one second and while cranking with jumped and relay?(just double checking) Do you have a Wide Open Throttle switch?(located on the throttle body by the bonnet and linkage) Book says to check MAP sensor but we can't even get 5V to it. Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 14 minutes ago, eaglescout526 said: Ok. Theres not a ballast resistor anywhere is there? And we have confirmed the pump runs for both one second and while cranking with jumped and relay?(just double checking) Do you have a Wide Open Throttle switch?(located on the throttle body by the bonnet and linkage) Book says to check MAP sensor but we can't even get 5V to it. No ballast resistor. Fuel pump continuously runs with jumper in relay socket. It does not run with relay in relay socket, regardless if cranking or not. As for if it runs with jumper while cranking, I couldn't tell you on the grounds that it cranks way too loud for me to hear the pump. However, now that the fuel pressure gauge is connected to throttle body, I can check to verify it is continuously running while cranking with jumper. I believe I do have a WOT. It's the small rectangular component that has a silver latch-looking thing that is hit by the throttle linkage, yes? Edit: Yes, while cranking, fuel pump retains 14-15PSI with jumper relay. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 5, 2020 Share Posted May 5, 2020 Correct. To test the WOT you need to unplug it from the harness. Test the on off operation using a DVOM Digital volt ohmmeter Operate the switch The resistance should be infinite when the throttle is closed. A low resistance should be indicated when at the WOT position Test the switch several times Replace if defective(I don't even know if that switch is available) Reconnect it to the harness With the ign on test the WOT switch voltage at D2_6 to ground/D2_7 There should be no voltage reading at WOT position: greater than 2 volts if not at the WOT position If no voltage is present in either position, test for a short to ground in the wire harness or switch Check for open circuit between T8 of the ECU and the switch connector Repair or replace harness if necessary If the voltage is always greater than 2 volts, test for an open circuit in the wire of connector between the switch and ground. Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 9 minutes ago, eaglescout526 said: Correct. To test the WOT you need to unplug it from the harness. Test the on off operation using a DVOM Digital volt ohmmeter Operate the switch The resistance should be infinite when the throttle is closed. A low resistance should be indicated when at the WOT position Test the switch several times Replace if defective(I don't even know if that switch is available) Reconnect it to the harness With the ign on test the WOT switch voltage at D2_6 to ground/D2_7 There should be no voltage reading at WOT position: greater than 2 volts if not at the WOT position If no voltage is present in either position, test for a short to ground in the wire harness or switch Check for open circuit between T8 of the ECU and the switch connector Repair or replace harness if necessary If the voltage is always greater than 2 volts, test for an open circuit in the wire of connector between the switch and ground. With harness disconnected, WOT sensor maintains 0.L with throttle closed. In WOT position, it steadily increases to 0.8 ohms, but no more. With harness reconnected and key ON, D2_6 & D2_7 = 5.04V (throttle closed) / 02.8mV (WOT position). Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 5, 2020 Share Posted May 5, 2020 Ok so the switch itself is good, low resistance at WOT and it should be infinite but I believe O.L. is the same, I think. Volt meters get weird around there. It passes the closed throttle voltage test but fails the WOT meaning there's something wrong with the harness which leads to testing for an open circuit in the wire or connector between the switch and ground. Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 3 minutes ago, eaglescout526 said: Ok so the switch itself is good, low resistance at WOT and it should be infinite but I believe O.L. is the same, I think. Volt meters get weird around there. It passes the closed throttle voltage test but fails the WOT meaning there's something wrong with the harness which leads to testing for an open circuit in the wire or connector between the switch and ground. And how might I do that? Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 5, 2020 Share Posted May 5, 2020 Hang on, uploading Pt II of the engine and fuel controls diagram that has the WOT, ISA and a few others. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 5, 2020 Share Posted May 5, 2020 T8 goes to D2_6 to WOT then to splice D which grounds out at G110. Where ever that ground is at. 88 replaces the WOT switch for the PS pressure switch. Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 7 minutes ago, eaglescout526 said: T8 goes to D2_6 to WOT then to splice D which grounds out at G110. Where ever that ground is at. 88 replaces the WOT switch for the PS pressure switch. Would that not be the dipstick stud ground? There aren't many ground points for RENIX, right? It's not the main engine ground, not the firewall ground, and I think the only other ground within the engine bay is the dipstick tube, yes? Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 5, 2020 Share Posted May 5, 2020 That's probably right, I just wonder why the couldn't label it more precise than just G110. But yes you have the ground post to engine block by alt bracket, then from bolt head to strap and then the dipstick ground, you also have that one on the drivers side fender but that does the blower motor, wiper motor and etc. Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 2 minutes ago, eaglescout526 said: That's probably right, I just wonder why the couldn't label it more precise than just G110. But yes you have the ground post to engine block by alt bracket, then from bolt head to strap and then the dipstick ground, you also have that one on the drivers side fender but that does the blower motor, wiper motor and etc. So what exactly do I test? Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 5, 2020 Share Posted May 5, 2020 An open circuit of some sort. So somewhere is an open circuit of either corrosion, damaged wire, loose or disconnected wires. Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 4 minutes ago, eaglescout526 said: An open circuit of some sort. So somewhere is an open circuit of either corrosion, damaged wire, loose or disconnected wires. I suppose I'll start slicing at the wire harness tomorrow. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 5, 2020 Share Posted May 5, 2020 Do you know if the truck has been attacked by rodents before? Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 2 minutes ago, eaglescout526 said: Do you know if the truck has been attacked by rodents before? I wouldn't know. But since she's been with me (circa July 2018), I haven't had a rodent problem where both the truck and myself have been residing. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 5, 2020 Share Posted May 5, 2020 Hmm, just wondering if maybe a small rodent got to a wire somewhere, alrighty. Lets try again tomorrow and see what we get. Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 12 hours ago, eaglescout526 said: Hmm, just wondering if maybe a small rodent got to a wire somewhere, alrighty. Lets try again tomorrow and see what we get. Some of the mess I'm dealing with. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 5, 2020 Share Posted May 5, 2020 I see why you were never looking forward to tearing into it....you got your work cut out for ya. Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 10 minutes ago, eaglescout526 said: I see why you were never looking forward to tearing into it....you got your work cut out for ya. As far as I can sift through on the relay side of the harness, basically where all the mess is in the picture, no wires seem to be fried by looks alone. The inside of all those connectors looks pretty pristine too. Link to comment Share on other sites More sharing options...
eaglescout526 Posted May 5, 2020 Share Posted May 5, 2020 Id be kinda surprised if nothing showed it self. This kind of ordeal makes me want to have a few 2.5L ECU's for testing/back up. Link to comment Share on other sites More sharing options...
Ωhm Posted May 5, 2020 Share Posted May 5, 2020 5vdc supply on TPS and MAP, is that still in question? Link to comment Share on other sites More sharing options...
SoCalManche Posted May 5, 2020 Author Share Posted May 5, 2020 3 minutes ago, Ωhm said: 5vdc supply on TPS and MAP, is that still in question? Correct. Edit: trying to rule out everything before ECU. Link to comment Share on other sites More sharing options...
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